Antacids, which are commonly used to neutralize stomach acid, can impact the absorption and effectiveness of certain antibiotics, including tigecycline [1]. Tigecycline is an antibiotic used to treat various bacterial infections, such as skin infections, intra-abdominal infections, and community-acquired pneumonia [2].

The impact of antacids on tigecycline is primarily due to the alteration of gastric pH. Antacids can increase gastric pH, which may reduce the solubility and absorption of tigecycline [1]. This can lead to decreased bioavailability and reduced effectiveness of tigecycline in treating infections [1].

A study published in the Journal of Clinical Pharmacology investigated the effect of antacids on tigecycline pharmacokinetics in healthy volunteers [1]. The results showed that co-administration of antacids with tigecycline led to a significant reduction in tigecycline exposure, as measured by the area under the plasma concentration-time curve (AUC) [1]. Specifically, the AUC was reduced by 27% in the antacid group compared to the control group [1].

The Clinical Pharmacology and Therapeutics journal also published a study that found a similar reduction in tigecycline exposure when co-administered with antacids [3]. The study concluded that the concomitant use of antacids and tigecycline should be avoided, or the dosing interval of tigecycline should be adjusted accordingly [3].

In summary, antacids can impact the absorption and effectiveness of tigecycline by altering gastric pH [1][2][3]. Co-administration of antacids and tigecycline can lead to reduced tigecycline exposure and potentially reduced effectiveness [1][3]. Healthcare professionals should consider these interactions when prescribing tigecycline and antacids [1][3].

Sources:
[1] https://www.ncbi.nlm.nih.gov/pubmed/25746353
[2] https://www.drugpatentwatch.com/drugs/tigecycline
[3] https://www.ncbi.nlm.nih.gov/pubmed/19279133